‘International Research Journal of Agricultural Science and Soil Science (ISSN: 2251-0044) Vol. 2(5) pp. 207-216, May 2012
Available online http://www.interesjournals.org/IRJAS
Copyright ©2012 International Research Journals
Full Length Research Paper
Nitrogen and potassium balances of newly opened
wetland rice field
Sukristiyonubowo1, Sofyan Ritung2 and Kusumo Nugroho2
1
Indonesian Soil Research Institute, Jalan Juanda 98 Bogor
Indonesian Centre of Agriculture Land Resources Research and Development
2
Accepted 09 May, 2012
Soils allocated for development of newly opened wetland rice fields in Indonesia can be from dry land
or/and wetland to meet rice growing demand. The soils are low in major nutrient contents, but high in
Fe concentration. The farmers do not apply N and K fertilisers’ bases on recommendation. The study
was conducted on newly opened wetland rice farming originated from wetland in Tanjung Buka SP-2
village, Bulungan District, East Kalimantan Province, Indonesia in 2011. The aims were (1) to evaluate
nitrogen and potassium input – out of newly opened wetland rice and (2) to validate the N and K
recommendation. The results indicated that surplus N ranged from 39.03 to 71.62 kg N ha-1 season-1,
meaning the amount of urea is more than enough to replace N removed by harvest product. The
recommended urea should be reduced to 150 kg urea with added compost of 3 tons ha-1 season-1. If the
compost increased to 3 tons ha-1 season-1, K fertilizer can be increased to 150 kg KCl ha-1 season-1 to
substitute K taken away by rice harvest product and to keep higher rice grain yield. These N and K
recommendation rate imply the total urea and KCl available at district level with about 1,477 tons urea
and 1,477 tons KCl district -1 season -1, respectively (150 kg urea x 9,849 ha and 150 kg KCl x 9,849 ha).
Keywords: Nutrient balance, plot scale, nutrient input, nutrient losses, newly opened wetland rice, wetland.
INTRODUCTION
The Indonesian Agriculture is challenge ahead in
producing more rice with limited land and water to meet
rice growing demand. Attentions should be addressed not
only to technical irrigated lowland rice system, but also to
other wetland rice system including newly opened
wetland rice fields outside Java and Bali Islands. Study
on nutrient balance in newly opened wetland rice
Indonesia is not yet carried out.
In Indonesia, dryland (utisols and inceptisols) and
wetland (potential acid sulphate soils) are mainly
allocated for development newly opened wetland rice
fields (Agus, 2007; Prasetyo, 2007; Hardjowigeno and
Rayes, 2005). These soils are acidic with low natural
level of major plant nutrients; however it has Fe in toxic
levels (Sukristiyonubowo et al., 2011a; Sukristiyonubowo
et al., 2012). More mineral and organic fertilizers are
required to improve nutrients level and unfortunately the
cost of inorganic fertilizers is too expensive.
Consequently, to keep crop production better, proper
*Corresponding Author E-mail: sukristiyonubowo@gmail.com
fertilizers recommendation are needed with more organic
matter, liming, and inorganic fertilizer (Sukristiyonubowo
et al., 2011a; Sukristiyonubowo et al., 2010;
Sukristiyonubowo and Tuherkih, 2009; Yan et al., 2007;
Fageria and Baligar, 2001). Therefore, it is critical to
assess nutrient input given and taken away from the field
to develop fertilizer recommendation. In addition,
quantification of nutrient inputs and outputs is also
important for agronomical, economical and environmental
analyses.
Nutrient balances can be defined as the differences
between nutrient gains and losses. Nutrients coming from
fertilizers, returned crop residues, irrigation, rainfall, and
biological nitrogen fixation are grouped as nutrient input
(Sukristiyonubowo et al., 2011b; Sukristiyonubowo et al.,
2010; Sukristiyonubowo. 2007; Wijnhoud et al. 2003;
Lefroy
and
Konboon,
1999).
According
to
Sukristiyonubowo
et
al.,
(2011b
and
2010),
Sukristiyonubowo (2007) and Uexkull (1989), nutrient
outputs included removal through harvested biomass (all
nutrients), erosion (all nutrients), leaching (mainly nitrate,
potassium, calcium and magnesium), fixation (mainly
phosphate), and volatilization (mainly nitrogen and
208 Int. Res. J. Agric. Sci. Soil Sci.
sulphur). When the nutrient removals are not substituted
by sufficient application of fertilizers or returning of
biomass, soil mining takes place and crop production do
not reach its potential yields and finally reduces.
Nutrient balances can be developed at different scales
and purposes, including (a) plot, (b) field, farm or
catchment, (c) district, province, and (d) country scale
(Sukristiyonubowo et al., 2011b; Sukristiyonubowo et al.,
2010; Lefroy and Konboon. 1999; Bationo et al. 1998;
Hashim et al. 1998; Van den Bosch et al. 1998a and
1998b; Syers .1996; Smaling et al. 1993; and Stoorvogel
et al. 1993). Many studies indicate that at plot, farm,
district, province, and national levels, agricultural
production is characterised by a negative nutrient
balance
(Sukristiyonubowo
et
al.,
2010;
Sukristiyonubowo, 2007; Nkonya et al., 2005; Sheldrick
et al., 2003; Harris. 1998; and Van den Bosch et al.,
1998b).
A complete study of nutrient balances is very
complicated. In a simple approach, the main inputs are
organic and mineral fertilizers while nutrient loss can be
calculated based on removal by harvested products and
unreturned crop residues.So far, it is reported that most
assessment is partial analysis of these in- and output
data (Wijnhoud et al., 2003; Drechsel et al., 2001; Lefroy
and Konboon, 1998).
Crop residue including rice residue is a fundamental
natural resource for conserving and sustaining soil
productivity. It supplies essential plant nutrients, improves
physical and biological conditions of the soil, and
prevents soil degradation (Sukristiyonubowo. 2007;
Aulakh et al., 2001; Puget and Drinkwater, 2001; Jastrow
et al., 1998; Tisdale and Oades, 1979; Walter et al.,
1992). However, the nutrients present in roots are often
discounted in nutrient balance assessment of cropping
systems. Most attention was paid to cover crops since
they are considered to be a potential source of nitrogen
for the following crops (Kumar and Goh, 2000; Thomsen,
1993; Harris and Hesterman, 1990). Now, it has been
observed that the contribution of plant nutrients from
roots is important, ranging between 13 and 40 % of total
plant
N
(Sukristiyonubowo
et
al.,
2011b;
Sukristiyonubowo. 2007; Chaves et al., 2004; Kumar and
Goh, 2000).
The study of nitrogen and potassium balances on
newly opened wetland rice field originated from wetland
at Tanjung Buka SP-2, Bulungan district, was aimed (a)
to evaluate nitrogen and potassium input – output of
newly opened wetland rice under different treatments and
(b) to validate the N and K recommended application
rates. It was hypothesized that proper N and K fertilizer
application rate based on N and K studies will lead to
optimal rice yield.
METHODOLOGY
Plot scale nitrogen and potassium balances of newly
opened wetland rice originated from wetland were
studied in Tanjung Buka SP-2 Village, Bulungan District,
East Kalimantan Province, Indonesia in 2011. The site
was relatively flat and developed in 2007. Seven
treatments were tested namely T0: farmers practices (as
control), T1: farmer practices + straw compost +
dolomite, T2: NPK with recommendation rate, in which P
was split two times, T3: NPK with recommendation rate +
straw compost, T4: NPK with recommendation rate, T5:
NPK with recommendation rate + straw compost +
dolomite and T6: NPK with recommendation rate in which
P was split two times. These treatments were constructed
according to the fact that soil fertility status was classified
as low; with low pH, low soil organic carbon. Farmers did
not apply P and K as recommendation rate or the farmers
did not apply K fertilizer. They were arranged in
Randomized Complete Block Design (RCBD) and
replicated three times. The plot sizes were 5m x 5m with
the distance among plot was 50 cm and between
replication was 100 cm. NPK fertilizer used originated
from single fertilizer namely urea, SP-36 (Super
Phosphate) and KCl (Potassium Chloride). Based on the
direct measurement with Soil Test Kits, the
recommendation rate was determined about 250 kg urea,
100 kg SP-36 and 100 kg KCl ha-1 season-1, while the
common farmer practices rate was 100 kg urea and 50
kg SP-36 ha-1 season-1. The urea and KCl were split
three times namely 50 % at planting time, 25 % at 21
DAT (days after planting) and the last 25 % was given at
-1
35 DAT. Dolomite as much as two tons ha and rice
-1
straw compost of about two tons ha were broadcasted a
week before planting. Only the treatments of T2 and T6,
P were applied two times: 50 % at planting time and 50
% was given at 21 DAT. In the farmer practices, N was
split two time, 50 % at planting time and 50 % at 21 DAT,
while for P was given one time at planting time. Before
broadcasting the compost, one kg composite compost
were taken and analysed for its chemical contents. The
detail treatments are presented in Table1.
Inpari 10 rice variety was cultivated as plant indicator.
Transplanting was carried out in the end of June 2011
and harvest in the first week of October 2011. Twentyone-day old seedlings were transplanted at about 25 cm
x 25 cm cropping distance with about three seedlings per
hill. Rice biomass productions including grains, straw,
and residues were measured at harvest. Sampling units
(1m x 1 m plot), were randomly selected at every plot.
Rice plants were cut about 15 cm above the ground
surface. The samples were manually separated into rice
grains, rice straw, and rice residues. Rice residues
included the roots and the part of the stem (stubble) left
after cutting. Fresh weights of rice grain, rice straw, and
rice residues were immediately weighed at harvest at
each sampling unit. In this input-output analysis, rice
residue was not considered as an input, as it is always
remained in the field.
The nutrient inputs were the sum of nutrients coming
from mineral fertiliser (IN-1), rice straw compost (IN-2),
Sukristiyonubowo et al. 209
Table 1. The detail treatment of NPK fertilization, dolomite and compost made of rice straw of newly opened rice field
originated from wetland.
Code
Treatment
T0
T1
T2
Farmer Practices (as control)
Farmer Practices+Compost+Dolomit
NPK with recommendation rate, in which
P was split two time
NPK with recommendation rate +
Compost
NPK with recommendation rate
NPK with recommendation rate +
Compost + Dolomite
NPK
with reccomendation rate +
compost + Dolomite, in which P was split
two times
T3
T4
T5
T6
irrigation (IN-3), and precipitation (IN-4). Outputs were
sum of nutrients removed by rice grains (OUT-1) and rice
straw (OUT-2). See formulas 1, 2 and 3
(Sukristiyonubowo et al. 2011b; Sukristiyonubowo. 2007)
Nutrient Inputs (IN) = IN-1 + IN-2 + IN-3 + IN-4
………………..……... (1)
Nutrient Outputs (OUT) = OUT-1 + OUT-2
...................……………... (2)
Nutrient
Balance
=
IN
–
OUT
……………………..………………….... (3)
To quantify nitrogen and potassium gains, data
included concentrations of N and K in urea and KCl, rate
of urea and KCl, amount of N and K in compost, irrigation
water supply, N and K concentrations in irrigation waters
and in rainfall were collected. The output parameters
were rice grain yields, rice straw production, N and K
concentrations in rice grain and rice straw.
IN-1 and IN-2 was calculated based on the amount of
mineral and organic fertilizers added multiplied by the
concentration of N and K in urea and KCl and compost,
respectively. IN-3 was estimated according to water
input and nutrients content in irrigation water. Water input
was the different between incoming water and outgoing
water. Incoming water was calculated by mean of water
discharge multiplied by time the inlet is open and close
the inlet and outlet during rice life cycle, mainly from land
soaking to repining stage. As the N and K concentrations
from the outlet were not measured, thus the contribution
of these nutrients from irrigation water was predicted
based on water input multiplied by the N and K contents
in incoming water, respectively. In this experiment, the
pounding water layer was maintained about three cm.
The water discharge was measured using Floating
method. IN-4 was estimated by multiplying rainfall volume
with nutrient concentrations in the rain water. In a hectare
basis, it was counted as follow:
IN-4 = A x 10.000 x 0.80 x B x 1000
6
1000 x 10
Urea
SP-36
KCl
Dolomite
Compost
-1
.....................................kg ha ................................
100
50
100
50
2000
2000
250
100
100
250
100
100
-
2000
250
250
100
100
100
100
2000
2000
250
100
100
2000
2000
Where:
-1
• IN-4 is N or K input of rainfall water in kg N and K ha
-1
season
• A is rainfall in mm
• 10000 is conversion of ha to m2
• 0.80 is correction factor, as not all rain water goes
into the soil
• B is N and K concentrations in rainfall water in mg l-1 ,
respectively
• 1000 is conversion from m3 to l
• 1000 is conversion from mm to m
6
• 10 is conversion from mg to kg
To monitor rainfall events, data from rain gauge and
climatology station of Bulungan were considered. Rain
waters were sampled once a month from a rain gauge in
600 ml plastic bottles and was also analysed according to
the procedures of the Laboratory of the Soil Research
Institute, Bogor (Soil Research Institute. 2009).
N and K losses can be through harvested product (rice
grain and rice straw). As all rice grains are transported
out of plots, OUT-1 was estimated based on rice grain
yield multiplied with N and K concentrations in the grains,
respectively. OUT-2 was calculated according to the total
rice straw production multiplied with N and K
concentrations in the straw, respectively. Rice straw was
considered as output because all rice straw was taken
out from the field for making compost and the compost
will be applied for coming planting season.
Plants were sampled at harvest and were collected
from every plot, one hill per plot. After pulling out, the
plant roots were washed with canal water. For the
laboratory analyses, the samples were treated according
to the procedures of the Analytical Laboratory of the Soil
Research Institute, Bogor. Samples were washed with
deionised water to avoid any contamination, and dried at
700 C. The dried samples were ground and stored in
plastic bottles. Nitrogen was determined by wet ashing
using concentrated H2SO4 (97%) and selenium. Potas-
210 Int. Res. J. Agric. Sci. Soil Sci.
Table 2. Chemical soil properties of newly opened wetland rice originated from wetland in Tanjung Buka SP-2
Village, Bulungan District established in 2007 (Soil taken in June 2011)
Parameter
pH
Organic Matter
Organic C
N
C/N ratio
P ekstrak HCl 25 %
K ekstrak HCl 25 %
P Bray I
CEC
K
Ca
Mg
Fe
Unit
%
%
ppm
ppm
ppm
-1
cmol (+) kg
-1
cmol (+) kg
cmol (+) kg-1
cmol (+) kg-1
ppm
sium was measured after wet ashing using HClO4 and
HNO3 (Soil Research Institute, 2009).
RESULTS AND DISCUSSION
Soil Properties
A chemical soil property of newly opened rice originated
from wetland in Tanjung Buka SP-2 village, where the
experiment was located, is given in Table 2. The pH was
very acid, varying between 3.78 and 4.50. The cation
exchange capacities (CEC) value ranged from 23 to 25
cmol+ kg-1 and it was categorised as high. The levels of
soil organic carbon (SOC) and total N were low, ranging
from 1.96 % to 2.10 % and from 0.20 to 0.60 %,
respectively. According to Sommerfeldt et al. (1988) and
Clark et al. (1998) observed higher soil OM levels in soils
managed with animal manure and cover crops than in
soils without such inputs.
Total P or potential P extracted with HCl 25% ranged
-1
from 58 to 79 mg P2O5 kg and these values may be
classified as very low. Furthermore, available P was also
very low, ranging between 11.61 and 19.61 mg P2O5 kg-1,
suggesting application of 100 kg SP-36 ha-1 season-1
increases the availability of P leading to soil function
improvement. Total K was low, varying from 129 to 176
mg K2O kg-1, indicating application of 100 kg KCl ha-1
-1
season also increase the total K in the soil. Clark et al.
(1998); Rasmussen and Parton (1994) and Wander et al.
(1994) also reported similar findings.
The concentrations of exchangeable Ca (1.36 – 5.49
cmol+ kg-1) and K (0.11 – 0.19 cmol+ kg-1) and
exchangeable Mg concentrations (1.73 - 2.61 cmol+ kg-1)
were low to medium. Considering the ratio of
exchangeable calcium, magnesium and potassium
percentage, the data also indicated an imbalanced ratio.
Site
Tanjung Buka SP-2
3,78 – 4.50
criteria
Tanjung Buka SP-2
Very acid
1.96 – 2.10
0,20 – 0.60
9.80
58 -79
129 - 176
11,61- 19.61
23 - 25
0.11 – 0.19
1.36 - 5,49
1,73 – 2.61
251 - 270
Low
Low
low
Very Low
Low
Very Low
High
Very Low
Low
Low to medium
High
In normal conditions, the ratio ranges from 60 to 65 % of
calcium, 10 to 15 % of magnesium, and 5 to 7 % of
potassium. Therefore, it may be concluded that in general
the chemical soil fertility was very low due to very acid
pH, very low organic matter content, and low available P
and K concentrations. Hence, applications of
recommended N, P and K fertilizers improve inherent soil
fertility leading to rice yield.
Nitrogen and potassium inputs
The N and K input originated from application of urea and
KCl (IN-1), compost (IN-2), irrigation water (IN-3) and
rainfall water (IN-4) and their nutrient contribution are
presented in Tables 3, 4 and 5. The IN-1 (contribution of
mineral fertilizer) was about + 45.00 for farmer practices
and + 112.50 kg N ha-1 season-1 for recommendation
-1
rates, while for potassium was about + 50.70 kg K ha
-1
season for recommendation rate. It can be said that the
higher rate of urea and KCl fertilizers, the higher their
contribution to the N and K inputs (Table 3).
-1
-1
The IN-2 was about + 21.00 kg N ha season , from
the mean of N content in compost of 1.56 %, 0.93 % and
0.67 % N, while for K was about 51.20 kg K ha-1 season-1,
from the K consentrations of 2.90 %, 2.92 % and 2.85 %
K (Table 2). Hence, besides the application rate of
compost, the N and K concentrations in compost
influenced the contribution. Therefore, it can also be
concluded that application of two tons compost ha-1
season-1 was relatively similar to application of 100 kg
-1
-1
KCl ha season , the KCl recommendation rate.
The quality of water for irrigation were considered
good contained of 2.35 mg l-1 NH4+, 0.76 mg l-1 K +, 0.03
-1
3-1
mg l P04 and 2,94 mg l N03 .
Nitrogen and potassium contribution inputs from
irrigation water (IN-3) was about 0.79 N kg ha-1 season-1
Sukristiyonubowo et al. 211
Table 3. The contribution of inorganic fertilizer (IN-1) and compost (IN-2) to P and K inputs, study on nutrient balance
of newly opened wetland rice originated from wetland of Tanjung Buka SP-2 at Bulungan District.
Treatment
T0
T1
T2
T3
T4
T5
T6
Rate of Fertilizer and Compost
-1
-1
(kg ha season )
Urea
100
100
250
250
250
250
250
KCl
100
100
100
100
100
contribution to N
(kg N
-1
-1
ha season )
Compost
2.000
2.000
2.000
2.000
2000
IN-1
45.00
45.00
112.50
112.50
112.50
112.50
112.50
IN-2
21.00
21.00
21.00
21.00
Contribution to K (kg K
-1
-1
ha season )
IN-1
50.70
50.70
50.70
50.70
50.70
IN-2
51.20
51.20
51.20
51.20
T0: Farmer Practices (as control)
T1: Farmer Practices + Compost + Dolomite;
T2: NPK with recommendation rate, in which P was split two times
T3: NPK with recommendation rate + Compost
T4: NPK with recommendation rate
T5: NPK with recommendation rate+ Compost + Dolomite
T6: NPK with recommendation rate + Compost + dolomite, in which P was spli two times
IN-1: N or K input of mineral fertilizer
IN-2: N or K input of compost
Table 4. The contribution of irrigation water (IN-3) to phosphorous and potassium input, study on nutrient balance of
newly opened wetland rice originated from wetland of Tanjung Buka SP-2 at Bulungan District.
Treatment
T0
T1
T2
T3
T4
T5
T6
Water input, P and K concentrations
Water input NH4+ NO3K Concen.
(L)
... mg l-1......
Mg l-1
6
15 x 10
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
15 x 106
2.35 2.94
0.76
Contribution to input
IN-3
(kg
IN-3
(kg
N ha-1season-1)
K ha-1season-1)
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
0.35 0.44 0.79
11.26
T0: Farmer Practices (as control)
T1: Farmer Practices + Compost + Dolomite;
T2: NPK with recommendation rate, in which P was split two times
T3: NPK with recommendation rate + Compost
T4: NPK with recommendation rate
T5: NPK with recommendation rate + Compost + Dolomite
T6: NPK with recommendation rate + Compost + dolomite, in which P was spli two times
IN-3: N or K input of irrigation water
equivalent to about 1.75 kg urea ha-1 season-1,
meanwhile for potassium was about 11.26 kg K ha-1
-1
-1
-1
season equivalent to about 22.52 kg KCl ha season (
Table 3), which was considered high, almost one fourth
of potassium fertilizer recommended rate.
The input coming from rain water was about 20.42 kg
N, equal to 45 kg urea and for potassium about 1.74 kg K
equal to 3.50 kg KCl ha-1 season-1 (Table 4), which were
considered insignificant. Similar results are reported in
terraced paddy field system in Semarang District of about
-1
-1
20.6 kg N and 6.1 kg K ha season (Sukristiyonubowo.
2007).
Nitrogen and potassium losses
N and K losses were estimated from rice grain (OUT-1)
and by rice straw (OUT-2) taken out from the plots. The N
and K loss are presented in Table 6 and 7.
N taken away by rice grain ranged between 22.50 and
-1
-1
53.50 kg N ha season depending on the rice grain
production. Meanwhile, nitrogen removed by rice straw
varied from 14.68 and 38.45 kg N ha-1 season-1(Tabel 6).
The highest N removed by rice grain and rice straw were
indicated by T6 (NPK with recommendation rate +
Compost + dolomite, in which P was spli two times). The
212 Int. Res. J. Agric. Sci. Soil Sci.
Table 5. The contribution of rainfall water (IN-4) to nitrogen and potassium input, study on nutrient balance of newly
opened wetland rice originated from wetland of Tanjung Buka SP-2 at Bulungan District.
Treatment
T0
T1
T2
T3
T4
T5
T6
Rainfall, N and K concentrations
+
Rainfall
NH4
K Concen.
-1
(mm)
( mg K l )
2,715
0.94
0.08
2,715
0.94
0.08
2,715
0.94
0.08
2,715
0.94
0.08
2,715
0.94
0.08
2,715
0.94
0.08
2,715
0.94
0.08
Contribution to input
IN-4
(kg
IN-4
(kg
-1
-1
-1
-1
N ha season )
K ha season )
20.42
1.74
20.42
1.74
20.42
1.74
20.42
1.74
20.42
1.74
20.42
1.74
20.42
1.74
T0: Farmer Practices (as control)
T1: Farmer Practices + Compost + Dolomite;
T2: NPK with recommendation rate, in which P was split two times
T3: NPK with recommendation rate + Compost
T4: NPK with recommendation rate
T5: NPK with recommendation rate + Compost + Dolomite
T6: NPK with recommendation rate + Compost + dolomite, in which P was spli two times
IN-4: N or KInput of rain water
total N taken away by harvest product of about 91.95 kg
N ha-1 season-1 was also indicated by T6 because of the
highest rice yield and rice straw of this treatment.
Therefore, it can be said that increasing rice harvest
product remove more nitrogen.
The similar results was shown by potassium, The
highest K removed by rice grain and rice straw were
indicated by T6 (NPK with recommendation rate +
Compost + dolomite, in which P was spli two times). The
total K taken away by harvest product of about 148.93 kg
K ha-1 season-1 was also indicated by T6 because of the
highest rice yield and rice straw of this treatment.
Therefore, it can be said that increasing rice harvest
product also remove more potassium (Table 7).
Output-Input Analysis
The N and K balances of newly opened wetland rice
originated from wetland are presented in Tables 8 and 9.
In general, the results indicated that inorganic fertiliser
(IN-1) contributes considerably to total N and K input in
all treatments. In the T0 to T6 treatments, IN-1
contributed to about 46 % to 84 % of total input of N and
from 40 to 68 % of total K inputs. Similar result was
observed in farmer practices rates (T0 and T1), which
contributed from 46 to 59 % of the total N inputs. It may
be greater in the newly opened wetland rice areas than in
the other wetland rice fields, as the inherent soil fertility of
newly opened wetland rice fields are classified low and
developed from highly weathered soils and potential
sulphate soils (Sukristiyonubowo et al. 2011)
Compost (IN-2) was also an important nutrient source,
covering about 14 % to 22 % of total N and from 41 to 68
% of total K input depending on the treatment. The IN-2
is more important, when less or no inorganic fertilisers
are applied and more organic fertiliser is added. Nutrient
supplied by compost was equivalent to 47 kg of urea and
about 101 kg KCl. This will be more when the rate of
compost application increased.
The IN-3 was considered insignificant for contribution
to nitrogen of about 1% from total input of N for all
treatment. However, the contributions of IN-3 to K inputs
were still important, covering between 16 % and 93 % of
the total K inputs.
Assessment of N input and output shows a positive
balance for all treatments (Table 8). The surplus of N
-1
-1
ranged between 39.03 and 71.62 kg N ha season . The
treatment T3 indicated the N balance in the highest
surplus. This may be explained by total inputs was the
highest the same as treatments T5 and T6 and the total
output (rice grain and straw productions) was considered
lower than T5 and T6. In contrast, K input and Output
analysis indicated negative balance for all treatments
(Table 9). The deficit ranged from – 2.50 to – 60.43 kg K
ha-1 season-1, depending on the treatment. For T2 and
T4, the K balance were also more negative than the
others. These are due to K taken away by rice grains and
rice straws. It was higher than other treatments and total
inputs because of no input from compost. Therefore, to
replace K taken out by rice harvest products, K fertilizer
application rate should be increased from 100 to 200 kg
-1
-1
KCl ha season when the rate of compost is not
increased. However, when the compost is increased from
-1
-1
2 tons to 3 tons ha season , K fertilizer application rate
could be increased from 100 to 150 kg KCl ha-1 season-1
as the compost from rice straw is rich in K. Regarding the
farmers condition, the last option is more feasible since
the rice straw is abundant in the fields.
The positive N balances in all treatments also demon-
Sukristiyonubowo et al. 213
Table 6. Rice biomass production including rice grain and rice straw of Inpari 10 variety and total N loss from rice
grain (OUT-1) and rice straw (OUT-2) at newly opened wetland rice originated from wetland of Tanjung Buka SP-2
site, Bulungan District (in kg N ha-1season-1)
Treatments
T0
T1
T2
T3
T4
T5
T6
Biomass Production
(t ha-1 season-1)
Rice Grain Rice Straw
2.05 c*)
2.33 c
3.15 b
2.97 b
3.93 a
4.20 a
4.02 a
4.17 a
3.88 a
3.97 a
4.11 a
4.22 a
4.18 a
4.32 a
N concentration
(%)
Rice Grain
Rice Straw
1.10
0.63
1.14
0.83
1.18
0.87
1.15
0.86
1.14
0.76
1.22
0.88
1.28
0.89
N loss
(kg N ha-1 season-1)
OUT-1
OUT-2
22.50
14.68
35.91
24.65
46.37
36.54
46.23
35.86
44.23
30.17
50.14
37.14
53.50
38.45
Total N loss
37.18
60.56
82.91
82.09
74.40
87.28
91.95
T0: Farmer Practices (as control)
T1: Farmer Practices + Compost + Dolomite;
T2: NPK with recommendation rate, in which P was split two times
T3: NPK with recommendation rate + Compost
T4: NPK with recommendation rate
T5: NPK with recommendation rate+ Compost + Dolomite
T6: NPK with recommendation rate + Compost + dolomite, in which P was spli two times
OUT-1: N losses by rice grain
OUT-2: N losses by rice straw
*) The mean values in the same column followed by the same letter are not statistically different
Table 7. Rice biomass production including rice grain and rice straw of Inpari 10 variety and total K loss from rice grain
(OUT-1) and rice straw (OUT-2) at newly opened wetland rice originated from of Tanjung Buka SP-2 site, Bulungan
District (in kg K ha-1season-1)
Treatments
T0
T1
T2
T3
T4
T5
T6
Biomass Production
( t ha-1 season-1)
Rice Grain Rice Straw
2.05 c*)
2.33 c
3.15 b
2.97 b
3.93 a
4.20 a
4.02 a
4.17 a
3.88 a
3.97 a
4.11 a
4.22 a
4.18 a
4.32 a
K concentration
(%)
Rice Grain Rice Straw
0.20
2.10
0.22
2.68
0.26
2.98
0.25
2.95
0.25
2.97
0.31
3.11
0.32
3.14
K loss
(kg K ha-1 season-1)
OUT-1
OUT-2
4.10
48.93
5.53
77.56
10.21
125.16
10.05
118.59
9.70
117.91
11.74
131.24
13.38
135.65
Total K loss
53.03
83.09
135.37
128.64
127.61
142.98
148.93
T0: Farmer Practices (as control)
T1: Farmer Practices + Compost + Dolomite;
T2: NPK with recommendation rate, in which P was split two times
T3: NPK with recommendation rate + Compost
T4: NPK with recommendation rate
T5: NPK with recommendation rate + Compost + Dolomite
T6: NPK with recommendation rate + Compost + dolomite, in which P was spli two times
OUT-1: K losses by rice grain
OUT-2: K losses by rice straw
*) The mean values in the same column followed by the same letter are not statistically different
strated that the application rates of urea were more than
enough to replace N removed by rice grains and straw.
Recommendation rate should be reduced to avoid any
negative impact and to reduce operational cost.
Therefore, to get better rice production, to prevent the
environment from pollution hazard and to keep soil
quality, N fertilizer application rate should be 200 kg ha-1
seson-1 or when compost increased from 2 to 3 ton ha-1
season-1, the N recommended rate is 150 kg ha-1season 1
. For potassium the application rate should be increased
from 100 to 200 kg KCl ha-1 season-1. However, as rice
straw was abandon in the rice fields and can easily be
composted, the K fertilizer can be increased to 150 kg
KCl ha-1 season-1 with adding more compost, from 2 to 3
-1
-1
ton ha season . It can be concluded that to sustain
higher rice yield, the recommendation rates are 150 kg
214 Int. Res. J. Agric. Sci. Soil Sci.
Table 8. Input-ooutput analysis for nitrogen of newly opened wetland rice originated from wetland of Tanjung Buka
SP-2 site, Bulungan District (kg N ha-1 season-1)
Parameter
T0
-1
-1
N INPUT (kg N ha season )
IN-1
+ 45.00
59%
IN-2
0%
IN-3
+ 0.79
1%
IN-4
+ 20.42
40%
Total Input
+ 76.21
100%
N OUTPUT(kg N ha-1 Season-1)
OUTPUT-1
- 22.50
60%
OUTPUT-2
- 14.68
40%
Total Output
- 37.18
100%
N Balance
+ 39.03
T1
T2
Treatments
T3
T4
T5
T6
+ 45.00
46%
+ 21.00
22%
+ 0.79
1%
+ 20.42
31%
+ 97.21
100%
+ 112.50
84%
0%
+ 0.79
1%
+ 20.42
15%
+ 133.71
100%
+ 112.50
73%
+ 21.00
14%
+ 0.79
1%
+ 20.42
13%
+ 153.71
100%
+112.50
84%
0%
+ 0.79
1%
+ 20.42
15%
+ 133.71
100%
+ 112.50
84%
+ 21.00
14%
+ 0.79
1%
+ 20.42
13%
+ 153.71
100%
+ 112.50
84%
+ 21.00
14%
0.79
1%
+ 20.42
13%
+ 153.71
100%
- 46.37
56%
- 36.54
44%
- 82.91
100%
+ 50.80
- 46.23
56%
- 35.86
44%
- 82.09
100%
+ 71.62
- 44.23
59%
- 30.17
41%
- 74.40
100%
+ 63.31
- 50.14
57%
- 37.14
43%
- 87.28
100%
+ 66.43
- 53.50
58%
- 38.45
42%
- 91.95
100%
+ 61.76
- 35.91
59%
- 24.65
41%
- 60.56
100%
+ 36.65
Table 9. Input-ooutput analysis for potassium of newly opened wetland rice originated from wetland of Tanjung Buka
SP-2 site, Bulungan District (kg K ha-1 season-1)
Treatment
Paramenter
To
T1
-1
-1
K INPUT (kg K ha season )
IN-1
IN-2
IN-3
-
T2
-
+ 51.20
68%
+ 22.50
30%
+ 1.74
2%
+ 75.44
100%
+ 22.50
93%
IN-4
+ 1.74
7%
Total Input
+ 24.24
100%
-1
K OUTPUT(kg K ha Season-1)
OUTPUT-1
- 4.10
- 5.53
8%
7%
OUTPUT-2
- 48.93
- 77.56
92%
93%
Total Output
- 53.03
- 83.09
100%
100%
Balance
- 29.79
- 8.65
T3
T4
T5
T6
+ 50.70
68%
0%
+ 22.50
30%
+ 1.74
2%
+ 74.94
100%
+ 50.70
40%
+ 51.20
41%
+ 22.50
16%
+ 1.74
3%
+ 126.14
100%
+ 50.70
68%
0%
+ 22.50
30%
+ 1.74
2%
+ 74.94
100%
+ 50.70
40%
+ 51.20
41%
+ 22.50
16%
+ 1.74
3%
+ 126.14
100%
+ 50.70
40%
+ 51.20
41%
+ 22.50
16%
+ 1.74
3%
+ 126.14
100%
- 10.21
8%
- 125.16
92%
- 135.37
100%
- 60.43
- 10.05
8%
-118.59
92%
- 128.64
100%
- 2.50
- 9.70
8%
- 117.91
92%
- 127.61
100%
- 52.67
- 11.74
8%
- 131.24
92%
- 142.98
100%
- 16.84
- 13.38
9%
- 135.65
91%
- 148.93
100%
- 22.79
Note: percentage in the same couloum indibated the contribution to to input/output
Sukristiyonubowo et al. 215
-1
-1
urea and 150 kg KCl ha season
-1
-1
season compost and 2 tons ha .
-1
with 3 tons ha
CONCLUSION
Assessment of N and K input and output of newly opened
wetland rice originated from wetland in Tanjung Buka SP2, Bulungan District indicated the surplus N ranged from
39.03 to 71.62 kg N ha-1 season-1, meaning that urea
application rate is more than enough to replace N
removed by harvest product. To obtain better rice
production and to improve soil function, N fertilizer
application rate should be reduced to 150 kg urea with
added more compost, up to of 3 tons ha-1 season-1.
Potassium application rate should be increased from 100
-1
-1
to 200 kg KCl ha season to fix K removed by harvest
product. However, when the compost will also be
increased to 3 tons ha-1 season-1 K fertilizer can be
increased to 150 kg KCl ha-1 season-1 to substitute K
removed by rice harvest product and to keep higher rice
grain yield. These N and K recommendation rate imply
that total urea and KCl should be available at district
level will be about 1,477 tons urea and 1,477 tons KCl
district -1 season -1, respectively (150 kg urea x 9,849 ha
and 150 kg KCl x 9,849 ha).
ACKOWLEDLEGMENT
We thank to the Minister of Research and Technology of
Republic of Indonesia for funding this experiment through
INSENTIF PROGRAM 2011. We thank also to Mr.
Suwandi and Mr. Rahmat Hidayat for spending their time
in the field.
REFERENCES
Agus F (2007). Pendahuluan. In: Agus, F., Wahyunto dan Santoso, D.
(eds.), Tanah Sawah Bukaan Baru. Balai Besar Litbang Sumberdaya
Lahan Pertanian. Departemen Pertanian. Hal. 1-4
Aulakh MS, TS Khera, JW Doran, KF Bronson (2001). Managing crop
residue with green, urea, and tillage in a rice-wheat rotation. Soil Sci.
Society Am. J. 65: 820-827
Bationo A, F Lompo, S Koala (1998). Research on nutrient flows and
balances in West Africa: State-of-the-art. Agricultural Water
Management. 71: 19-35
Chaves B, S De Neve, G Hofman, P Boeckx, OV Clemput (2004).
Nitrogen mineralisation of vegetables roots residues and green
manures as related to their (bio) chemical composition. Eur. J. Agron.
21: 161-170
Clark MS, WR Horwath, C Shennan, KM Scow (1998). Changes in soil
chemical properties resulting from organic and low-input farming
practices. Agron. J. 90: 662-671
Drechsel P, Dagmar Kunze, FP de Vries (2001). Soil nutrient depletion
and population growth in Sub-Saharan Africa: A Malthusian Nexus?
Population and Environment: J. Interdiscipl. Studies. 22 (4): 411-423.
Fan XH, YS Song, DX Lin, LZ Yang, JF Lou (2006). Ammonia
volatilisation losses and N-15 balance from urea applied to rice on a
paddy soil. J. Environ. Sci. China. 18 (2): 299-303
Fageri NK, CV Balligar (2001). Improving nutrient use efficiency of
annual crops in Brazilian acid soils for sustainable crop production.
Communication Soil Science Plan Analysis. 32 (7 and 8): 1301 1319
Hardjowigeno S, Rayes L (2005). Tanah Sawah. Bayumedia Publishing.
205 p.
Harris FMA (1998). Farm-level assessment of the nutrient balance in
northern Nigeria. Agriculture, Ecosystems and Environment 71: 201214
Harris GH, OB Hesterman (1990). Quantifying the nitrogen contribution
from alfalfa to soil and two succeeding crops using nitrogen-15.
Agron. J. 82: 129-134
Hashim GM, KJ Caughlan, JK Syers (1998). On-site nutrient depletion:
An effect and a cause of soil erosion. In: Penning de Vries, F.W.T.,
Agus, F., and Kerr, J. (Eds.), Soil Erosion at Multiple Scale. Principles
and Methods for Assessing Causes and Impacts. CABI Publishing in
Association with IBSRAM. pp. 207-222
Jastrow JD, RM Miller, J Lussenhop (1998. Contributions of interacting
biological mechanisms to soil aggregate stabilisation in restored
prairie. Soil Biology Biochemistry. 30: 905-916
Kumar K, KM Goh (2000). Biological nitrogen fixation, accumulation of
soil nitrogen, and nitrogen balance for white clover (Trifolium repens
L.) and field pea (Pisum sativum L.) grown for seed. Field Crop
Research. 68: 49-59
Lefroy RDB, Konboon J (1999). Studying nutrient flows to assess
sustainability and identify areas of nutrient depletion and imbalance:
an example for rainfed rice systems in Northeast Thailand. In: Ladha
(Eds.), Rainfed Lowland Rice: Advances in Nutrient Management
Research. IRRI, pp. 77-93
Nkonya E, Kaizzi C, Pender J (2005). Determinants of nutrient balances
in a maize farming system in eastern Uganda. Agricultural System.
85: 155-182
Prasetyo BH (2007). Genesis Tanah Sawah Bukaan Baru. F. Agus,
Wahyunto dan D. Santoso (Penyunting). Balai Besar Litbang
Sumberdaya Lahan Pertanian. Badan Litbang Pertanian. Bogor. Hal.
25-51.
Puget P, LE Drinkwater (2001). Short-term dynamics of root- and shootderived carbon from a leguminous green manure. Soil Sci. Soc. Am.
J. 65: 771-779
Rasmussen PE, Parton WJ (1994). Long-term effects of residue
management in wheat-fallow: I. Inputs, yields, and soil organic
matter. Soil Sci. Soc. Am. J. 58: 523-530
Santoso D, IGP Wigena, Z Eusof, X.H. Chen. 1995. The ASIALAND
management of sloping lands network: Nutrient balance study on
sloping lands. In: International Workshop on Conservation Farming
for Sloping Uplands in Southeast Asia: Challenges, Opportunities,
and Prospects. IBSRAM-Thailand Proceedings. 14: 93-108
Sheldrick WF, J Keith Syers, J Lingard (2003). Soil nutrient audits for
China to estimate nutrient balance and output/input relationships.
Agriculture, Ecosystems and Environment. 94: 341-354
Smaaling EMA, JJ Stoorvogel, PN Wiindmeijer 1993. Calculating soil
nutrient balances in Africa at different scales II. District scale.
Fertiliser Research. 35 (3): 237-250
Soil Research Institute (2009). Penuntun analisa kimia tanah, tanaman,
air dan pupuk (Procedure to measure soil chemical, plant, water and
fertiliser). Soil Research Institute, Bogor. 234 p. (in Indonesian)
Sommerfeldt TG, Chang C, Entz T (1988). Long-term annual manure
applications increase soil organic matter and nitrogen, and decrease
carbon to nitrogen ratio. Soil Sci. Soc. Am. J. 52: 1668-1672
Stoorvogel JJ, EMA Smaaling, BH Janssen (1993). Calculating soil
nutrient balances in Africa at different scales. I. Supra-national scale.
Fertiliser Research. 35 (3): 227-236
Sukristiyonubowo, Mulyadi P Wigena, A Kasno (1993). Effect of organic
matter, lime and NPK fertilizer added on soil properties and yield og
peanut. J. Ind. Soil and Fert. 11: 1 – 7 (in Indonesia)
Sukristiyonubowo (2007). Nutrient balances in terraced paddy fields
under traditional irrigation in Indonesia. PhD thesis. Faculty of
Bioscience Engineering, Ghent University, Ghent, Belgium. 184 p.
Sukristiyonubowo, E Tuherkih (2009). Rice production in terraced paddy
field systems. Jurnal Penelitian Pertanian Tanaman Pangan. 28(3):
139-147
Sukristiyonubowo, G Du Laing, MG Verloo (2010). Nutrient balances of
wetland rice for the Semarang District. J. Sustainable Agric. 34 (8):
850-861
216 Int. Res. J. Agric. Sci. Soil Sci.
Sukristiyonubowo, Ibrahim AS, Tagus V, Agus S (2011a). Management
of inherent soil fertility of newly opened wetland rice fields for
sustainable rice farming in Indonesia. J. Plant Breeding and Crop Sci.
3 (8): 146-153
Sukristiyonubowo, Fadhli Y, Agus S (2011b). Plot scale nitrogen
balance of newly opened wetland rice at Bulungan District. J. Agric.
Sci. Soil Sci. 1 (7): 234-241
Syers JK (1996). Nutrient budgets: uses and abuses. In Soil data for
sustainable land uses: A training workshop for Asia. IBSRAMThailand Proceedings. 15: 163-168
Thomsen IK (1993). Nitrogen uptake in barley after spring incorporation
of 15N labelled Italian ryegrass into sandy soils. Plant Soil. 150: 193201
Tisdall JM, JM Oades (19790. Stabilisation of soil aggregates by the
root systems of ryegrass. Aust. J. Soil Res. 29: 729-743
Uexkull HR von (1989). Nutrient cycling. In Soil Management and
Smallholder Development in the Pacific Islands. IBSRAM-Thailand
Proceedings. 8: 121-132
Van den Bosch H, A. de Joger, J Vlaming (1998a). Monitoring nutrient
flows and economic performance in African farming systems
(NUTMON) II. Tool Development. Agriculture, Ecosystems and
Environment. 71: 49-62
Van den Bosch H, JN Gitari, VN Ogoro, S Maobe, J Vlaming (1998b).
Monitoring nutrient flows and economic performance in African
farming systems (NUTMON) III. Monitoring nutrient flows and
balances in three districts in Kenya. Agriculture, Ecosystems and
Environment. 71: 63-80
Walters DT, MS Aulkh, JW Doran (1992). Effect of soil aeration, legume
residue and soil texture on transformations of macro and
micronutrients in soils. Soil Science. 153: 100-107
Wander MM, Traina SJ, Stinner BR, Peters SE (1994). Organic and
conventional management effects on biologically active organic
matter pools. Soil Sci. Soc. Am. J. 58: 1130-1139
Whitbread AM, GJ Blair, Rod DB Lefroy (2000). Managing legume leys,
residues and fertilisers to enhance the sustainability of wheat
cropping system in Australia. 1. The effects on wheat yields and
nutrient balance. Soil and Tillage Research. 54: 63 - 75
Wijnhoud JD, Konboon Y, Lefroy RDB (2003). Nutrient budgets:
Sustainability assessment of rainfed lowland rice-based systems in
northeast Thailand. Agriculture, Ecosystems and Environment. 100:
119-127
Yan D, D Wang, L Yang (2007). Long term effect chemical fertiliser,
straw and manure on labile organic matter in a paddy soil. Biol. Fertil.
Soil J. 44:93-101